Prenatal diagnosis of cystic fibrosis in South Africa.

Prenatal diagnosis of cystic fibrosis (CF) has been made possible by the finding that the activity of various enzymes derived from the microvillar membranes of the fetus is decreased in 2nd trimester amniotic fluid. Gamma-glutamyl transpeptidase, aminopeptidase M and the phenylalanine-inhibitable form of alkaline phosphatase (AP) have been found to be of most diagnostic use in this respect, the odds of the fetus being affected with CF being 28:1 if the AP test is positive. When couples have already had a child with CF, pregnancies are being monitored by these methods at the University of Cape Town.